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Merge tag 'v3.3.7' into 3.3/master
[zen-stable.git] / arch / s390 / kernel / module.c
blobdfcb3436bad069d9dd75290d54c868b92a2d6beb
1 /*
2 * arch/s390/kernel/module.c - Kernel module help for s390.
3 *
4 * S390 version
5 * Copyright (C) 2002, 2003 IBM Deutschland Entwicklung GmbH,
6 * IBM Corporation
7 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8 * Martin Schwidefsky (schwidefsky@de.ibm.com)
9 *
10 * based on i386 version
11 * Copyright (C) 2001 Rusty Russell.
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 */
27 #include <linux/module.h>
28 #include <linux/elf.h>
29 #include <linux/vmalloc.h>
30 #include <linux/fs.h>
31 #include <linux/string.h>
32 #include <linux/kernel.h>
33 #include <linux/moduleloader.h>
34 #include <linux/bug.h>
35
36 #if 0
37 #define DEBUGP printk
38 #else
39 #define DEBUGP(fmt , ...)
40 #endif
41
42 #ifndef CONFIG_64BIT
43 #define PLT_ENTRY_SIZE 12
44 #else /* CONFIG_64BIT */
45 #define PLT_ENTRY_SIZE 20
46 #endif /* CONFIG_64BIT */
47
48 /* Free memory returned from module_alloc */
49 void module_free(struct module *mod, void *module_region)
50 {
51 if (mod) {
52 vfree(mod->arch.syminfo);
53 mod->arch.syminfo = NULL;
54 }
55 vfree(module_region);
56 }
57
58 static void
59 check_rela(Elf_Rela *rela, struct module *me)
60 {
61 struct mod_arch_syminfo *info;
62
63 info = me->arch.syminfo + ELF_R_SYM (rela->r_info);
64 switch (ELF_R_TYPE (rela->r_info)) {
65 case R_390_GOT12: /* 12 bit GOT offset. */
66 case R_390_GOT16: /* 16 bit GOT offset. */
67 case R_390_GOT20: /* 20 bit GOT offset. */
68 case R_390_GOT32: /* 32 bit GOT offset. */
69 case R_390_GOT64: /* 64 bit GOT offset. */
70 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
71 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
72 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
73 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
74 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
75 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
76 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
77 if (info->got_offset == -1UL) {
78 info->got_offset = me->arch.got_size;
79 me->arch.got_size += sizeof(void*);
80 }
81 break;
82 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
83 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
84 case R_390_PLT32: /* 32 bit PC relative PLT address. */
85 case R_390_PLT64: /* 64 bit PC relative PLT address. */
86 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
87 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
88 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
89 if (info->plt_offset == -1UL) {
90 info->plt_offset = me->arch.plt_size;
91 me->arch.plt_size += PLT_ENTRY_SIZE;
92 }
93 break;
94 case R_390_COPY:
95 case R_390_GLOB_DAT:
96 case R_390_JMP_SLOT:
97 case R_390_RELATIVE:
98 /* Only needed if we want to support loading of
99 modules linked with -shared. */
100 break;
101 }
102 }
103
104 /*
105 * Account for GOT and PLT relocations. We can't add sections for
106 * got and plt but we can increase the core module size.
107 */
108 int
109 module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
110 char *secstrings, struct module *me)
111 {
112 Elf_Shdr *symtab;
113 Elf_Sym *symbols;
114 Elf_Rela *rela;
115 char *strings;
116 int nrela, i, j;
117
118 /* Find symbol table and string table. */
119 symtab = NULL;
120 for (i = 0; i < hdr->e_shnum; i++)
121 switch (sechdrs[i].sh_type) {
122 case SHT_SYMTAB:
123 symtab = sechdrs + i;
124 break;
125 }
126 if (!symtab) {
127 printk(KERN_ERR "module %s: no symbol table\n", me->name);
128 return -ENOEXEC;
129 }
130
131 /* Allocate one syminfo structure per symbol. */
132 me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym);
133 me->arch.syminfo = vmalloc(me->arch.nsyms *
134 sizeof(struct mod_arch_syminfo));
135 if (!me->arch.syminfo)
136 return -ENOMEM;
137 symbols = (void *) hdr + symtab->sh_offset;
138 strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset;
139 for (i = 0; i < me->arch.nsyms; i++) {
140 if (symbols[i].st_shndx == SHN_UNDEF &&
141 strcmp(strings + symbols[i].st_name,
142 "_GLOBAL_OFFSET_TABLE_") == 0)
143 /* "Define" it as absolute. */
144 symbols[i].st_shndx = SHN_ABS;
145 me->arch.syminfo[i].got_offset = -1UL;
146 me->arch.syminfo[i].plt_offset = -1UL;
147 me->arch.syminfo[i].got_initialized = 0;
148 me->arch.syminfo[i].plt_initialized = 0;
149 }
150
151 /* Search for got/plt relocations. */
152 me->arch.got_size = me->arch.plt_size = 0;
153 for (i = 0; i < hdr->e_shnum; i++) {
154 if (sechdrs[i].sh_type != SHT_RELA)
155 continue;
156 nrela = sechdrs[i].sh_size / sizeof(Elf_Rela);
157 rela = (void *) hdr + sechdrs[i].sh_offset;
158 for (j = 0; j < nrela; j++)
159 check_rela(rela + j, me);
160 }
161
162 /* Increase core size by size of got & plt and set start
163 offsets for got and plt. */
164 me->core_size = ALIGN(me->core_size, 4);
165 me->arch.got_offset = me->core_size;
166 me->core_size += me->arch.got_size;
167 me->arch.plt_offset = me->core_size;
168 me->core_size += me->arch.plt_size;
169 return 0;
170 }
171
172 static int
173 apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
174 struct module *me)
175 {
176 struct mod_arch_syminfo *info;
177 Elf_Addr loc, val;
178 int r_type, r_sym;
179
180 /* This is where to make the change */
181 loc = base + rela->r_offset;
182 /* This is the symbol it is referring to. Note that all
183 undefined symbols have been resolved. */
184 r_sym = ELF_R_SYM(rela->r_info);
185 r_type = ELF_R_TYPE(rela->r_info);
186 info = me->arch.syminfo + r_sym;
187 val = symtab[r_sym].st_value;
188
189 switch (r_type) {
190 case R_390_8: /* Direct 8 bit. */
191 case R_390_12: /* Direct 12 bit. */
192 case R_390_16: /* Direct 16 bit. */
193 case R_390_20: /* Direct 20 bit. */
194 case R_390_32: /* Direct 32 bit. */
195 case R_390_64: /* Direct 64 bit. */
196 val += rela->r_addend;
197 if (r_type == R_390_8)
198 *(unsigned char *) loc = val;
199 else if (r_type == R_390_12)
200 *(unsigned short *) loc = (val & 0xfff) |
201 (*(unsigned short *) loc & 0xf000);
202 else if (r_type == R_390_16)
203 *(unsigned short *) loc = val;
204 else if (r_type == R_390_20)
205 *(unsigned int *) loc =
206 (*(unsigned int *) loc & 0xf00000ff) |
207 (val & 0xfff) << 16 | (val & 0xff000) >> 4;
208 else if (r_type == R_390_32)
209 *(unsigned int *) loc = val;
210 else if (r_type == R_390_64)
211 *(unsigned long *) loc = val;
212 break;
213 case R_390_PC16: /* PC relative 16 bit. */
214 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */
215 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */
216 case R_390_PC32: /* PC relative 32 bit. */
217 case R_390_PC64: /* PC relative 64 bit. */
218 val += rela->r_addend - loc;
219 if (r_type == R_390_PC16)
220 *(unsigned short *) loc = val;
221 else if (r_type == R_390_PC16DBL)
222 *(unsigned short *) loc = val >> 1;
223 else if (r_type == R_390_PC32DBL)
224 *(unsigned int *) loc = val >> 1;
225 else if (r_type == R_390_PC32)
226 *(unsigned int *) loc = val;
227 else if (r_type == R_390_PC64)
228 *(unsigned long *) loc = val;
229 break;
230 case R_390_GOT12: /* 12 bit GOT offset. */
231 case R_390_GOT16: /* 16 bit GOT offset. */
232 case R_390_GOT20: /* 20 bit GOT offset. */
233 case R_390_GOT32: /* 32 bit GOT offset. */
234 case R_390_GOT64: /* 64 bit GOT offset. */
235 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
236 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
237 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
238 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
239 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
240 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
241 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
242 if (info->got_initialized == 0) {
243 Elf_Addr *gotent;
244
245 gotent = me->module_core + me->arch.got_offset +
246 info->got_offset;
247 *gotent = val;
248 info->got_initialized = 1;
249 }
250 val = info->got_offset + rela->r_addend;
251 if (r_type == R_390_GOT12 ||
252 r_type == R_390_GOTPLT12)
253 *(unsigned short *) loc = (val & 0xfff) |
254 (*(unsigned short *) loc & 0xf000);
255 else if (r_type == R_390_GOT16 ||
256 r_type == R_390_GOTPLT16)
257 *(unsigned short *) loc = val;
258 else if (r_type == R_390_GOT20 ||
259 r_type == R_390_GOTPLT20)
260 *(unsigned int *) loc =
261 (*(unsigned int *) loc & 0xf00000ff) |
262 (val & 0xfff) << 16 | (val & 0xff000) >> 4;
263 else if (r_type == R_390_GOT32 ||
264 r_type == R_390_GOTPLT32)
265 *(unsigned int *) loc = val;
266 else if (r_type == R_390_GOTENT ||
267 r_type == R_390_GOTPLTENT)
268 *(unsigned int *) loc =
269 (val + (Elf_Addr) me->module_core - loc) >> 1;
270 else if (r_type == R_390_GOT64 ||
271 r_type == R_390_GOTPLT64)
272 *(unsigned long *) loc = val;
273 break;
274 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
275 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
276 case R_390_PLT32: /* 32 bit PC relative PLT address. */
277 case R_390_PLT64: /* 64 bit PC relative PLT address. */
278 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
279 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
280 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
281 if (info->plt_initialized == 0) {
282 unsigned int *ip;
283 ip = me->module_core + me->arch.plt_offset +
284 info->plt_offset;
285 #ifndef CONFIG_64BIT
286 ip[0] = 0x0d105810; /* basr 1,0; l 1,6(1); br 1 */
287 ip[1] = 0x100607f1;
288 ip[2] = val;
289 #else /* CONFIG_64BIT */
290 ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */
291 ip[1] = 0x100a0004;
292 ip[2] = 0x07f10000;
293 ip[3] = (unsigned int) (val >> 32);
294 ip[4] = (unsigned int) val;
295 #endif /* CONFIG_64BIT */
296 info->plt_initialized = 1;
297 }
298 if (r_type == R_390_PLTOFF16 ||
299 r_type == R_390_PLTOFF32 ||
300 r_type == R_390_PLTOFF64)
301 val = me->arch.plt_offset - me->arch.got_offset +
302 info->plt_offset + rela->r_addend;
303 else {
304 if (!((r_type == R_390_PLT16DBL &&
305 val - loc + 0xffffUL < 0x1ffffeUL) ||
306 (r_type == R_390_PLT32DBL &&
307 val - loc + 0xffffffffULL < 0x1fffffffeULL)))
308 val = (Elf_Addr) me->module_core +
309 me->arch.plt_offset +
310 info->plt_offset;
311 val += rela->r_addend - loc;
312 }
313 if (r_type == R_390_PLT16DBL)
314 *(unsigned short *) loc = val >> 1;
315 else if (r_type == R_390_PLTOFF16)
316 *(unsigned short *) loc = val;
317 else if (r_type == R_390_PLT32DBL)
318 *(unsigned int *) loc = val >> 1;
319 else if (r_type == R_390_PLT32 ||
320 r_type == R_390_PLTOFF32)
321 *(unsigned int *) loc = val;
322 else if (r_type == R_390_PLT64 ||
323 r_type == R_390_PLTOFF64)
324 *(unsigned long *) loc = val;
325 break;
326 case R_390_GOTOFF16: /* 16 bit offset to GOT. */
327 case R_390_GOTOFF32: /* 32 bit offset to GOT. */
328 case R_390_GOTOFF64: /* 64 bit offset to GOT. */
329 val = val + rela->r_addend -
330 ((Elf_Addr) me->module_core + me->arch.got_offset);
331 if (r_type == R_390_GOTOFF16)
332 *(unsigned short *) loc = val;
333 else if (r_type == R_390_GOTOFF32)
334 *(unsigned int *) loc = val;
335 else if (r_type == R_390_GOTOFF64)
336 *(unsigned long *) loc = val;
337 break;
338 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */
339 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */
340 val = (Elf_Addr) me->module_core + me->arch.got_offset +
341 rela->r_addend - loc;
342 if (r_type == R_390_GOTPC)
343 *(unsigned int *) loc = val;
344 else if (r_type == R_390_GOTPCDBL)
345 *(unsigned int *) loc = val >> 1;
346 break;
347 case R_390_COPY:
348 case R_390_GLOB_DAT: /* Create GOT entry. */
349 case R_390_JMP_SLOT: /* Create PLT entry. */
350 case R_390_RELATIVE: /* Adjust by program base. */
351 /* Only needed if we want to support loading of
352 modules linked with -shared. */
353 break;
354 default:
355 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
356 me->name, r_type);
357 return -ENOEXEC;
358 }
359 return 0;
360 }
361
362 int
363 apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
364 unsigned int symindex, unsigned int relsec,
365 struct module *me)
366 {
367 Elf_Addr base;
368 Elf_Sym *symtab;
369 Elf_Rela *rela;
370 unsigned long i, n;
371 int rc;
372
373 DEBUGP("Applying relocate section %u to %u\n",
374 relsec, sechdrs[relsec].sh_info);
375 base = sechdrs[sechdrs[relsec].sh_info].sh_addr;
376 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr;
377 rela = (Elf_Rela *) sechdrs[relsec].sh_addr;
378 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
379
380 for (i = 0; i < n; i++, rela++) {
381 rc = apply_rela(rela, base, symtab, me);
382 if (rc)
383 return rc;
384 }
385 return 0;
386 }
387
388 int module_finalize(const Elf_Ehdr *hdr,
389 const Elf_Shdr *sechdrs,
390 struct module *me)
391 {
392 vfree(me->arch.syminfo);
393 me->arch.syminfo = NULL;
394 return 0;
395 }